1. Field of the Invention
This invention relates in general to a turbocharged internal combustion engine, and more particularly to an improvement in an air regulator system arranged to supply a required amount of air to engine combustion chambers through an intake air bypass passageway bypassing a throttle valve during engine warming-up.
2. Description of the Prior Art
In connection with a turbocharged internal combustion engine equipped with a turbocharger whose compressor wheel is disposed in an intake air passageway leading to engine combustion chambers, it is well known that air is fed to the engine combustion chambers through an intake air bypass passageway bypassing a throttle valve disposed in the intake air passageway downstream of the turbocharger compressor wheel during engine warming-up in which an air regulator disposed in the bypass passageway is opened. However, when the pressure prevailing in the intake passageway downstream of the throttle valve is higher than that in the intake passageway upstream of the compressor wheel, there arises a possibility that intake air reverse flow occurs toward the upstream side of the turbocharger compressor wheel through the bypass passageway, thereby lowering the supercharging efficiency of the turbocharger.